Please refer to FIG. 1(a), which is a diagram illustrating a conventional master-slave current distribution circuit applying in the parallel power supply, wherein the master-slave current distribution circuit 1 includes a voltage amplifier 11, an impedor 12, a power converting unit 13, a current detecting unit 14, an equivalent diode 15, an adjustable amplifier 16 and an adding unit 17. When the master-slave current distribution circuit 1 is electrically connected to the parallel power supply including the power supplies PS1 and PS2, the object of the stable distribution of the output voltages and output currents thereof is achieved by the master-slave current distribution circuit 1.
An energy gap voltage is needed to be applied to the master-slave current distribution circuit 1 for preventing a parallel error which would result in an unstable output voltages therefrom. The parallel error in the master-slave current distribution circuit 1 is generated between the power supplies PS1 and PS2. For example, the equivalent diode 15, which is a discrete component in the master-slave current distribution circuit 1, will generate an non-linear voltage in the linear operation range (around 0˜0.4V). The non-linear voltage generated by the equivalent diode 15 induces a parallel error in the master-slave current distribution circuit 1. Therefore, the parallel error problems would be solved when the energy gap voltage is applied to the master-slave current distribution circuit 1. But if the energy gap voltage is high, the unstable phenomenon in the output voltage of the power supplies PS1 and PS2 would be induced. In other words, the parallel error in the master-slave current distribution circuit 1 is induced by the high energy gap voltage.
For overcoming the mentioned drawbacks, the Application Specific Integrated Circuit (ASIC) is applied in a conventional master-slave current distribution circuit to decrease the operation voltage of the discrete component therein. The adopted energy gap voltage is hence to be kept in a low voltage range. However, the requirement of the energy gap voltages for different parallel power supplies are different, so as in the requirement of the energy gap voltages for different integrated circuits. Therefore, the result in using ASIC to decrease the energy gap voltage is limited as shown in FIG. 1(b). Accordingly, the present invention provides an improved master-slave current distribution circuit to overcome the drawbacks in the prior art.